INFO: rcu detected stall in __hrtimer_run_queues (3)

Status: upstream: reported C repro on 2026/08/08 20:09
Subsystems: kernel
Labels: prio:high
[Documentation on labels]
Reported-by: syzbot+6d991f16f4bcc8eeea24@syzkaller.appspotmail.com
First crash: 294d, last: 2d13h
▶ ▼ ✨ AI Jobs (2)
ID Workflow Result Correct Bug Created Started Finished Revision
82282e71 assessment-security DenialOfService: ✅ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ✅ UserNamespace: ✅ VMGuestTrigger: ❌ VMHostTrigger: ❌ ❓ INFO: rcu detected stall in __hrtimer_run_queues (3) 2026/05/18 03:46 2026/05/18 03:46 2026/05/18 04:28 de5aae85
1c26bc29 repro ❓ INFO: rcu detected stall in __hrtimer_run_queues (3) 2026/03/08 09:38 2026/03/08 09:38 2026/03/08 09:49 31e9c887
▶ ▼ Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [kernel?] INFO: rcu detected stall in __hrtimer_run_queues (3) 3 (5) 2026/09/04 22:32
▶ ▼ Similar bugs (7)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in __hrtimer_run_queues kernel 1 syz, C inconclusive done 22 1477d 2023d 0/29 auto-obsoleted due to no activity on 2022/12/19 03:45
linux-5.15 INFO: rcu detected stall in __hrtimer_run_queues 1 1 30d 30d 0/3 upstream: reported on 2026/08/07 07:45
upstream INFO: rcu detected stall in __hrtimer_run_queues (2) kernel 1 1 431d 431d 0/29 auto-obsoleted due to no activity on 2025/09/29 21:02
upstream BUG: soft lockup in __hrtimer_run_queues (4) kernel 1 1 522d 518d 0/29 auto-obsoleted due to no activity on 2025/06/30 23:58
upstream BUG: soft lockup in __hrtimer_run_queues (2) kernel 1 1 798d 794d 0/29 auto-obsoleted due to no activity on 2024/09/27 22:42
upstream BUG: soft lockup in __hrtimer_run_queues (3) kernel 1 1 615d 611d 0/29 auto-obsoleted due to no activity on 2025/03/30 03:09
upstream BUG: soft lockup in __hrtimer_run_queues kernel 1 2 2060d 2104d 0/29 auto-closed as invalid on 2021/04/15 12:33
▶ ▼ Cause bisection attempts (1)
Created Duration User Patch Repo Result
2026/09/02 04:58 0m bisect upstream error

Sample crash report:
watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [syz-executor:4831]
Modules linked in:
irq event stamp: 38640849
hardirqs last  enabled at (38640848): [<ffff800080557cd8>] seqcount_lockdep_reader_access+0x7c/0xf8 include/linux/seqlock.h:75
hardirqs last disabled at (38640849): [<ffff80008690cd0c>] __el1_irq arch/arm64/kernel/entry-common.c:527 [inline]
hardirqs last disabled at (38640849): [<ffff80008690cd0c>] el1_interrupt+0x28/0x60 arch/arm64/kernel/entry-common.c:543
softirqs last  enabled at (147672): [<ffff80008013891c>] local_bh_enable include/linux/bottom_half.h:33 [inline]
softirqs last  enabled at (147672): [<ffff80008013891c>] put_cpu_fpsimd_context arch/arm64/kernel/fpsimd.c:251 [inline]
softirqs last  enabled at (147672): [<ffff80008013891c>] do_sve_acc+0x32c/0x4b8 arch/arm64/kernel/fpsimd.c:1349
softirqs last disabled at (148217): [<ffff8000800204c0>] __do_softirq+0x14/0x20 kernel/softirq.c:656
CPU: 0 UID: 0 PID: 4831 Comm: syz-executor Not tainted syzkaller #0 PREEMPT 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/07/2026
pstate: 43400005 (nZcv daif +PAN -UAO +TCO +DIT -SSBS BTYPE=--)
pc : trace_hrtimer_expire_exit include/trace/events/timer.h:321 [inline]
pc : __run_hrtimer kernel/time/hrtimer.c:2035 [inline]
pc : __hrtimer_run_queues+0x32c/0xbe0 kernel/time/hrtimer.c:2096
lr : arch_static_branch arch/arm64/include/asm/jump_label.h:36 [inline]
lr : trace_hrtimer_expire_exit include/trace/events/timer.h:321 [inline]
lr : __run_hrtimer kernel/time/hrtimer.c:2035 [inline]
lr : __hrtimer_run_queues+0x32c/0xbe0 kernel/time/hrtimer.c:2096
sp : ffff80008eb67de0
x29: ffff80008eb67e40 x28: 1fffe00034bb7c3a x27: ffff0001a5dbe1c0
x26: ffff0000c6453a90 x25: ffff0000d1a50d38 x24: dfff800000000000
x23: 0000000000000001 x22: ffff800084ec6bd4 x21: 1fffe00018c8a752
x20: ffff0000c64545a8 x19: ffff0000c6453a80 x18: 0000000000000000
x17: ffff80011d2d8000 x16: ffff80008eb60000 x15: 0000000000000000
x14: 00000000ffff8000 x13: 0000000000000001 x12: 0000000000000000
x11: 0000000000000000 x10: 0000000000000102 x9 : 0000000000000101
x8 : 0000000000000000 x7 : 0000000000000000 x6 : 0000000000000000
x5 : 0000000000000001 x4 : 0000000000000008 x3 : ffff80008046a634
x2 : 0000000000000001 x1 : ffff0000c6453a80 x0 : 0000000000000000
Call trace:
 arch_static_branch arch/arm64/include/asm/jump_label.h:36 [inline] (P)
 trace_hrtimer_expire_exit include/trace/events/timer.h:321 [inline] (P)
 __run_hrtimer kernel/time/hrtimer.c:2035 [inline] (P)
 __hrtimer_run_queues+0x32c/0xbe0 kernel/time/hrtimer.c:2096 (P)
 hrtimer_run_softirq+0x15c/0x21c kernel/time/hrtimer.c:2113
 handle_softirqs+0x2ec/0xd98 kernel/softirq.c:622
 __do_softirq+0x14/0x20 kernel/softirq.c:656
 ____do_softirq+0x14/0x20 arch/arm64/kernel/irq.c:78
 call_on_irq_stack+0x30/0x48 arch/arm64/kernel/entry.S:885
 do_softirq_own_stack+0x20/0x2c arch/arm64/kernel/irq.c:83
 invoke_softirq kernel/softirq.c:503 [inline]
 __irq_exit_rcu+0x1ac/0x428 kernel/softirq.c:735
 irq_exit_rcu+0x14/0x84 kernel/softirq.c:752
 __el1_irq arch/arm64/kernel/entry-common.c:531 [inline]
 el1_interrupt+0x40/0x60 arch/arm64/kernel/entry-common.c:543
 el1h_64_irq_handler+0x18/0x24 arch/arm64/kernel/entry-common.c:548
 el1h_64_irq+0x6c/0x70 arch/arm64/kernel/entry.S:586
 __daif_local_irq_restore arch/arm64/include/asm/irqflags.h:175 [inline] (P)
 arch_local_irq_restore arch/arm64/include/asm/irqflags.h:195 [inline] (P)
 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:178 [inline] (P)
 _raw_spin_unlock_irqrestore+0x44/0x98 kernel/locking/spinlock.c:198 (P)
 __debug_check_no_obj_freed lib/debugobjects.c:1180 [inline]
 debug_check_no_obj_freed+0x2c8/0x3a4 lib/debugobjects.c:1201
 slab_free_hook mm/slub.c:2608 [inline]
 slab_free mm/slub.c:6377 [inline]
 kmem_cache_free+0x120/0x6b8 mm/slub.c:6504
 file_free+0x128/0x1dc fs/file_table.c:104
 __fput+0x538/0x74c fs/file_table.c:525
 fput_close_sync+0x10c/0x278 fs/file_table.c:617
 __do_sys_close fs/open.c:1511 [inline]
 __se_sys_close fs/open.c:1496 [inline]
 __arm64_sys_close+0x80/0x110 fs/open.c:1496
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x98/0x244 arch/arm64/kernel/syscall.c:49
 el0_svc_common+0xec/0x23c arch/arm64/kernel/syscall.c:121
 do_el0_svc+0x4c/0x5c arch/arm64/kernel/syscall.c:140
 el0_svc+0x64/0x260 arch/arm64/kernel/entry-common.c:758
 el0t_64_sync_handler+0x44/0x104 arch/arm64/kernel/entry-common.c:777
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:590
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 4802 Comm: kworker/1:3 Not tainted syzkaller #0 PREEMPT 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/07/2026
Workqueue: rcu_gp process_srcu
pstate: 83400005 (Nzcv daif +PAN -UAO +TCO +DIT -SSBS BTYPE=--)
pc : __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:179 [inline]
pc : _raw_spin_unlock_irqrestore+0x44/0x98 kernel/locking/spinlock.c:198
lr : __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:178 [inline]
lr : _raw_spin_unlock_irqrestore+0x38/0x98 kernel/locking/spinlock.c:198
sp : ffff80008eb77dc0
x29: ffff80008eb77dc0 x28: 1fffe00034bbc63a x27: ffff0001a5de31c0
x26: ffff0001a5de31d0 x25: ffff0000d2a4a538 x24: dfff800000000000
x23: 0000000000000001 x22: ffff800084ec6bd4 x21: ffff0001a5de2d80
x20: ffff0001a5de2d80 x19: 0000000000000000 x18: 00000000ffffffff
x17: ffff80008a7d6000 x16: 0000000000000002 x15: ffff80008a35fda0
x14: ffff80008a5d5e28 x13: 0000000000000001 x12: 0000000000000000
x11: ffff80008a5d5e28 x10: 0000000000000003 x9 : 0000000000000000
x8 : 00000000000000c0 x7 : 0000000000000000 x6 : 0000000000000000
x5 : 0000000000000001 x4 : 0000000000000008 x3 : ffff80008015611c
x2 : 0000000000000002 x1 : ffff0000d32c9d40 x0 : ffff80011d2fd000
Call trace:
 __daif_local_irq_restore arch/arm64/include/asm/irqflags.h:175 [inline] (P)
 arch_local_irq_restore arch/arm64/include/asm/irqflags.h:195 [inline] (P)
 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:178 [inline] (P)
 _raw_spin_unlock_irqrestore+0x44/0x98 kernel/locking/spinlock.c:198 (P)
 __run_hrtimer kernel/time/hrtimer.c:2028 [inline]
 __hrtimer_run_queues+0x22c/0xbe0 kernel/time/hrtimer.c:2096
 hrtimer_run_softirq+0x15c/0x21c kernel/time/hrtimer.c:2113
 handle_softirqs+0x2ec/0xd98 kernel/softirq.c:622
 __do_softirq+0x14/0x20 kernel/softirq.c:656
 ____do_softirq+0x14/0x20 arch/arm64/kernel/irq.c:78
 call_on_irq_stack+0x30/0x48 arch/arm64/kernel/entry.S:885
 do_softirq_own_stack+0x20/0x2c arch/arm64/kernel/irq.c:83
 invoke_softirq kernel/softirq.c:503 [inline]
 __irq_exit_rcu+0x1ac/0x428 kernel/softirq.c:735
 irq_exit_rcu+0x14/0x84 kernel/softirq.c:752
 __el1_irq arch/arm64/kernel/entry-common.c:531 [inline]
 el1_interrupt+0x40/0x60 arch/arm64/kernel/entry-common.c:543
 el1h_64_irq_handler+0x18/0x24 arch/arm64/kernel/entry-common.c:548
 el1h_64_irq+0x6c/0x70 arch/arm64/kernel/entry.S:586
 __daif_local_irq_restore arch/arm64/include/asm/irqflags.h:175 [inline] (P)
 arch_local_irq_restore arch/arm64/include/asm/irqflags.h:195 [inline] (P)
 queue_delayed_work_on+0xf4/0x140 kernel/workqueue.c:2624 (P)
 queue_delayed_work include/linux/workqueue.h:714 [inline]
 srcu_reschedule+0x240/0x338 kernel/rcu/srcutree.c:1957
 process_srcu+0xd04/0x1eb8 kernel/rcu/srcutree.c:1991
 process_one_work kernel/workqueue.c:3322 [inline]
 process_scheduled_works+0x788/0x10b8 kernel/workqueue.c:3405
 worker_thread+0x798/0xbd0 kernel/workqueue.c:3486
 kthread+0x304/0x3d4 kernel/kthread.c:436
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:838
watchdog: BUG: soft lockup - CPU#1 stuck for 26s! [kworker/1:3:4802]
Modules linked in:
irq event stamp: 44430735
hardirqs last  enabled at (44430734): [<ffff800086932074>] __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:178 [inline]
hardirqs last  enabled at (44430734): [<ffff800086932074>] _raw_spin_unlock_irqrestore+0x38/0x98 kernel/locking/spinlock.c:198
hardirqs last disabled at (44430735): [<ffff80008690cd0c>] __el1_irq arch/arm64/kernel/entry-common.c:527 [inline]
hardirqs last disabled at (44430735): [<ffff80008690cd0c>] el1_interrupt+0x28/0x60 arch/arm64/kernel/entry-common.c:543
softirqs last  enabled at (6136): [<ffff80008030e6e4>] softirq_handle_end kernel/softirq.c:468 [inline]
softirqs last  enabled at (6136): [<ffff80008030e6e4>] handle_softirqs+0xc28/0xd98 kernel/softirq.c:650
softirqs last disabled at (7461): [<ffff8000800204c0>] __do_softirq+0x14/0x20 kernel/softirq.c:656

Crashes (35):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/31 15:54 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci f1b8fa82cab7 2f52988a .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 BUG: soft lockup in __hrtimer_run_queues
2026/08/25 19:54 upstream 66498c75b4f8 614e416a .config console log report syz / log [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: rcu detected stall in __hrtimer_run_queues
2026/08/20 05:24 upstream 98f21c54f995 1e72964b .config strace log report syz / log [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: rcu detected stall in __hrtimer_run_queues
2026/08/07 05:50 net 594d90519502 c38879ea .config console log report syz / log [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: rcu detected stall in __hrtimer_run_queues
2026/08/24 12:43 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 21d6ac051080 1e72964b .config console log report syz / log [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 BUG: soft lockup in __hrtimer_run_queues
2026/08/24 06:05 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 21d6ac051080 1e72964b .config console log report syz / log [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 BUG: soft lockup in __hrtimer_run_queues
2026/09/03 23:01 upstream 841e384b841a 6a988719 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: rcu detected stall in __hrtimer_run_queues
2026/09/02 13:02 upstream 89a312991dc6 85995287 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: rcu detected stall in __hrtimer_run_queues
2026/09/01 18:49 upstream 786262be6048 587f6b29 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: rcu detected stall in __hrtimer_run_queues
2026/09/01 14:48 upstream 786262be6048 316d9396 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: rcu detected stall in __hrtimer_run_queues
2026/08/31 08:19 upstream a23cbb05744b 2f52988a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: rcu detected stall in __hrtimer_run_queues
2026/08/28 14:09 upstream 1b78070aaef6 bcbc8ceb .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: rcu detected stall in __hrtimer_run_queues
2026/08/27 07:34 upstream 73e3f0710014 a2b77b9e .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: rcu detected stall in __hrtimer_run_queues
2026/08/27 07:34 upstream 73e3f0710014 a2b77b9e .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: rcu detected stall in __hrtimer_run_queues
2026/08/27 07:34 upstream 73e3f0710014 a2b77b9e .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: rcu detected stall in __hrtimer_run_queues
2026/08/21 13:19 upstream 7f063b2f17ea 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: rcu detected stall in __hrtimer_run_queues
2026/07/27 07:15 upstream 4235cb24ec1e 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: rcu detected stall in __hrtimer_run_queues
2026/06/21 00:35 upstream 1a3746ccbb0a 43bfcdb0 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: rcu detected stall in __hrtimer_run_queues
2026/06/17 09:28 upstream 6b5a2b7d9bc1 62cc6db3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: rcu detected stall in __hrtimer_run_queues
2026/06/15 20:07 upstream 0e0611827f33 50bb0618 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: rcu detected stall in __hrtimer_run_queues
2026/05/19 02:15 upstream 4d3a2a466b8d 9f74d399 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: rcu detected stall in __hrtimer_run_queues
2026/05/02 22:18 upstream f1a5e78a55eb a0d91488 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: rcu detected stall in __hrtimer_run_queues
2026/01/18 05:58 upstream e84d960149e7 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: rcu detected stall in __hrtimer_run_queues
2026/01/18 04:52 upstream d3eeb99bbc99 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: rcu detected stall in __hrtimer_run_queues
2026/01/06 20:28 upstream f0b9d8eb98df d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: rcu detected stall in __hrtimer_run_queues
2025/12/05 14:12 upstream 2061f18ad76e d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: rcu detected stall in __hrtimer_run_queues
2025/11/24 13:19 upstream ac3fd01e4c1e bf6fe8fe .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: rcu detected stall in __hrtimer_run_queues
2025/11/18 03:06 upstream e7c375b18160 ef766cd7 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: rcu detected stall in __hrtimer_run_queues
2025/11/16 04:16 upstream f824272b6e3f f7988ea4 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: rcu detected stall in __hrtimer_run_queues
2026/02/10 13:17 bpf 05f7e89ab973 91d776d3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-bpf-kasan-gce BUG: soft lockup in __hrtimer_run_queues
2026/08/08 11:23 linux-next 6b8c8af514d7 5d63f80b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root BUG: soft lockup in __hrtimer_run_queues
2026/01/19 01:09 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing fa3bb5011f33 20d37d28 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb BUG: soft lockup in __hrtimer_run_queues
2026/01/07 05:56 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing e46bcc4e856e d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb BUG: soft lockup in __hrtimer_run_queues
2025/12/21 20:01 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing dd1fbe324a54 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb BUG: soft lockup in __hrtimer_run_queues
2026/08/07 11:00 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci db788396cbb1 e4ef95d6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 BUG: soft lockup in __hrtimer_run_queues
* Struck through repros no longer work on HEAD.